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Microstructural Benefits of Rsp in a γ-(Ti-Ta-Al) Alloy

Published online by Cambridge University Press:  28 February 2011

C. McCullough
Affiliation:
Materials Department, University of California, Santa Barbara CA 93106
J.J. Valencia
Affiliation:
Materials Department, University of California, Santa Barbara CA 93106
C.G. Levi
Affiliation:
Materials Department, University of California, Santa Barbara CA 93106
R. Mehrabian
Affiliation:
Materials Department, University of California, Santa Barbara CA 93106
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Abstract

Ti-15Ta-48Al alloy samples were characterized after arc melting, controlled supercooling experiments and splat-quenching. It was found that primary b.c.c. (β) forms from the melt in all cases. The arc-button exhibits severe Ta segregation toward the dendrite cores which is substantially alleviated by rapid solidification. Increasing bulk supercooling of the melt reduces the size and scale of segregation and ultimately results in a single phase γ structure. Splat quenching also increases homogeneity and alters the post-solidification transformations in three ways: (i) it suppresses the typical precipitation of γt laths in α2, (ii) it inhibits the formation of σ, and (iii) the Ta-rich areas of the β phase transform to B2 instead of α + σ.

Type
Research Article
Copyright
Copyright © Materials Research Society 1991

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